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United States Patent | 6,095,652 |
Trayner ,   et al. | August 1, 2000 |
A projection system incorporating a screen (2, 14) with a substantially achromatic response in a direction substantially perpendicular to the plane of the screen. The screen (2, 14) comprises a diffraction grating (4), means (5) for attenuating zero order and a diffuse holographic optical element (6). The system further comprises a focusing element with positive optical power. The aggregate optical power of the grating and the holographic optical element is substantially less than that of the focusing element.
Inventors: | Trayner; David John (London, GB); Orr; Edwina Margaret (London, GB) |
Assignee: | Richmond Holographic Research and Development, Ltd. (London, GB) |
Appl. No.: | 043241 |
Filed: | June 12, 1998 |
PCT Filed: | September 15, 1995 |
PCT NO: | PCT/GB95/02184 |
371 Date: | June 12, 1998 |
102(e) Date: | June 12, 1998 |
PCT PUB.NO.: | WO97/10523 |
PCT PUB. Date: | March 20, 1997 |
Current U.S. Class: | 353/10; 353/79; 359/15; 359/33; 359/446 |
Intern'l Class: | G03B 021/14 |
Field of Search: | 353/7,10,79,94,97,122 359/32.15,33,34,446,448,445,460,478 |
4799739 | Jan., 1989 | Newswanger. | |
4993790 | Feb., 1991 | Vick. | |
5198895 | Mar., 1993 | Vick | 358/103. |
5717522 | Feb., 1998 | Hattori et al. | 359/465. |
5760955 | Jun., 1998 | Goldenberg et al. | 359/456. |
5796499 | Aug., 1998 | Wenyon | 359/15. |
5798866 | Aug., 1998 | CeVaan | 359/621. |
5828471 | Oct., 1998 | Davis et al. | 359/15. |
5868480 | Feb., 1999 | Zeinali | 353/31. |
5943166 | Aug., 1999 | Hoshi et al. | 359/475. |
Foreign Patent Documents | |||
349 884 A2 | Jun., 1989 | EP. | |
349 947 A2 | Jul., 1989 | EP. | |
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